CAJ Innovations Forums - Testing of Board

sign216 Full Member Offline Posts: 175	Testing of Board 03/05/12 at 09:57:30 I finished the board (except for Q5) and did the testing. All were good, except for these discrepancies. 4. How can I see the square wave on T5? Do I need an oscilloscope? 5. Left pins of the FETs were 0, except for Q1 and Q2, which were 0.02 volt. The voltage at R28 was 0, and never went to 5V. How serious are these differences?
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YaBB Administrator YaBB Administrator Offline I love YaBB! Posts: 676 The Land of YaBB	Re: Testing of Board Reply #1 - 03/05/12 at 17:11:47 Its a bit hard to see the square wave without an oscilloscope but its not too important. It's the tacho signal. 0.02 volts is ok There could be an error in the notes. How about R28B. This is the fuel pump FET drive.
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sign216 Full Member Offline Posts: 175	Re: Testing of Board Reply #2 - 03/05/12 at 22:41:36 Ok, thanks for the tip. I'm just getting into work now (I'm in Boston, Massachusetts, USA). Tonight when I get home I'll try it out.
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sign216 Full Member Offline Posts: 175	Re: Testing of Board Reply #3 - 03/06/12 at 11:30:10 Yes, at R28b it goes to 5V after applying power, and then drops to 0. I installed Q5, and did test 6. What is meant by the phrase - "...should see the voltage regulator (bottom of D1) input above the battery voltage"? When I checked there, I got a voltage of 7.8V, and falling. Battery voltage was 8.5V.
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sign216 Full Member Offline Posts: 175	Re: Testing of Board Reply #4 - 03/06/12 at 23:28:50 Test 6 -D1 at bottom (stripe end) should give higher than battery voltage, right? I'm getting less, 7.8v, and it falls quickly. Top end of D1 is 5V, and steady. If that helps. Any ideas on what the issue is?
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Re: Testing of Board
Reply #5 - 03/07/12 at 07:05:22

That voltage should not fall. It is the battery voltage minus the drop of the Polyswitch and the inductor so it should be close to battery.
If it is dropping perhaps the battery is dead. Alternatively the ECU is drawing too much current and the Polyswitch is kicking in. Does the poly get warm? Current draw should be less than 100mA. Check your draw.

Q5 is the element that creates the voltage boost. With 12V in you should see 14-15.

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sign216 Full Member Offline Posts: 175	Re: Testing of Board Reply #6 - 03/07/12 at 09:37:03 The battery gives 8.9V and tests as 75% full on a battery meter. The polyswitch does not heat up. Circuit draws 78 mA. Below is a photo of my MOV and Polyswitch. Are they connected to the correct terminals? http://www.flickr.com/photos/sign216/6813995830/lightbox/
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Re: Testing of Board
Reply #7 - 03/07/12 at 12:01:22

sign216 wrote on 03/07/12 at 09:37:03:

The battery gives 8.9V and tests as 75% full on a battery meter.
The polyswitch does not heat up.
Circuit draws 78 mA.

Below is a photo of my MOV and Polyswitch. Are they connected to the correct terminals?

www.flickr.com/photos/sign216/6813995830/lightbox/

I'm testing it with a small 9V battery, per the instructions.

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YaBB Administrator YaBB Administrator Offline I love YaBB! Posts: 676 The Land of YaBB	Re: Testing of Board Reply #8 - 03/07/12 at 12:37:41 75mA is ok and the photo looks ok. I think your battery is struggling with the load. You don't mention what its voltage is when doing the test so i assume you are just measure the battery at no load. 75mA is a high load for a 9V battery. I suggest using it because the potential to turn the ECU into a molten mess is low.
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sign216 Full Member Offline Posts: 175	Re: Testing of Board Reply #9 - 03/07/12 at 13:11:05 Any ideas why I'm not getting a voltage boost at D1, but a 1V voltage loss.
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sign216 Full Member Offline Posts: 175	Re: Testing of Board Reply #10 - 03/12/12 at 12:41:21 I'm not getting a voltage boost when I test at D1. I'm going to order a new transistor at Q5 (2N7000) from a supply store, and hope that's the problem. Any other ideas? Any other parts I should replace, while I'm making a parts order?
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YaBB Administrator YaBB Administrator Offline I love YaBB! Posts: 676 The Land of YaBB	Re: Testing of Board Reply #11 - 03/12/12 at 14:32:33 What battery did you test with. Q5 is not reversed is it? So long as nothing is frying you should ignore this for the moment. Just make sure your bike battery is charged and warm the bike on your existing ECU.
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sign216 Full Member Offline Posts: 175	Re: Testing of Board Reply #12 - 03/13/12 at 04:35:09 Testing with a standard 9v battery, the kind used in common transistor radios. I'll check to make sure Q5 isn't reversed, but I'm pretty sure I put it down just like the diagram on the board. Work sent for away for two weeks (aargh). When I get back I'll ignore this issue for now, and see if the unit will run a warm bike.
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sign216 Full Member Offline Posts: 175	Re: Testing of Board Reply #13 - 03/29/12 at 01:19:30 I purchased a new transistor for Q5 (2N7000), installed it, and tested again. Same results; only 7.6 to 7.8 volts. There must be a different error in the voltage boost circuit.
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YaBB Administrator YaBB Administrator Offline I love YaBB! Posts: 676 The Land of YaBB	Re: Testing of Board Reply #14 - 03/29/12 at 07:09:15 What voltage do you see on the gate ( check 10K next to it ) Lets skip if for the moment. We can see later what it does with a 12V battery.
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